feat: PostScript stream processing with account code injection

tests/test_kyofilter.py

@@ -37,3 +37,45 @@ class TestGetAccountCode:
 
     def test_non_numeric_code_returns_none(self):
         assert kyofilter.get_account_code({"KmManagment": "MGabc45"}) is None
+
+
+class TestProcessStream:
+    def _stream(self, text):
+        return iter(line.encode() for line in text.splitlines(keepends=True))
+
+    def _collect(self, text, code):
+        return b"".join(kyofilter.process_stream(self._stream(text), code))
+
+    def test_passthrough_when_no_code(self):
+        ps = "%!PS\n%%BeginSetup\n%%EndSetup\n%%Page: 1 1\n"
+        assert self._collect(ps, None) == ps.encode()
+
+    def test_injects_before_end_setup(self):
+        ps = "%!PS\n%%BeginSetup\n%%EndSetup\n%%Page: 1 1\n"
+        result = self._collect(ps, "00012345")
+        assert b"(00012345) statusdict /setmanagementnumber get exec\n%%EndSetup\n" in result
+
+    def test_end_setup_preserved_after_injection(self):
+        ps = "%!PS\n%%BeginSetup\n%%EndSetup\n"
+        result = self._collect(ps, "00012345")
+        assert b"%%EndSetup\n" in result
+
+    def test_fallback_injects_before_first_page_when_no_end_setup(self):
+        ps = "%!PS\n%%Page: 1 1\nshowpage\n"
+        result = self._collect(ps, "00012345")
+        assert b"(00012345) statusdict /setmanagementnumber get exec\n%%Page: 1 1\n" in result
+
+    def test_injects_only_once(self):
+        ps = "%!PS\n%%BeginSetup\n%%EndSetup\n%%Page: 1 1\n%%Page: 2 1\n"
+        result = self._collect(ps, "00012345")
+        assert result.count(b"setmanagementnumber") == 1
+
+    def test_content_before_injection_point_preserved(self):
+        ps = "%!PS\n%%BeginSetup\n/mydict 10 dict def\n%%EndSetup\n"
+        result = self._collect(ps, "00012345")
+        assert b"/mydict 10 dict def\n" in result
+
+    def test_content_after_injection_point_preserved(self):
+        ps = "%!PS\n%%BeginSetup\n%%EndSetup\nshowpage\n"
+        result = self._collect(ps, "00012345")
+        assert b"showpage\n" in result